Control system for gas burners



Nov; 25, 1941.

. H. J. LONG CONTROL SYSTEM FOR GAS BURNERS Fil ed Jan. 28, 1939 ATTORNEY Patented Nov. 25, 1941 UNITED [r OFFICE 2 Claims.

This invention relates to a control system for the main valve of a gas burner, and more particularly to a control system of the type in which the pressure of the gas in the supply line is utilized to actuate the main gas valve in response to the temperature of the substance heated or to other operating conditions.

Pressure actuated gas valves and systems for their control in response to various operating conditions are well known. In my prior Patent 1,467,049 I disclosed a gas valve controlled by a diaphragm and adapted to close, due to an equalization of pressure on the two sides thereof, upon extinction of the pilot light. In this and in other diaphragm type valves as heretofore constructed, the closing of the valve has been dependent upon the presence of pressure on the diaphragm. Any failure or leakage of pipes or tubes conducting the gas to the diaphragm chamber tended to keep the gas valve open, with the consequent waste of gas and danger of overheating the appliance served by the burner.

It is among the objects of the present invention to overcome the above mentioned defects and provide a system in which the opening of the main gas valve is efiected by the pressure of the gas while the closure of this valve is dependent upon the absence of pressure. Accordingly, failure of the controlling pressure from any cause whatever results in the closure of the main gas valve and consequent cutting off of the fuel supply to the main burner.

It is a further object of this invention to provide an improved means whereby the gas valve is opened gradually to permit the spreading of the pilot flame to all of the orifices of the main burner prior to the full flow of gas thereto. In my Patent 2,135,585 I have disclosed one means for efiecting this function. The present invention achieves the same result in a novel and simplified manner, without complicating the system or adding to the working parts thereof.

It is a further object of the invention to pro-' vide a pressure actuated main gas valve in which the necessity for stufiing boxes or the like surrounding the stem of the valve is eliminated. The numerous operating difficulties which arise from the sticking of the main gas valve are thereby avoided.

The above and other objects and features of the invention will be apparent to those skilled in the art from a consideration of the following detailed description taken in conjunction with the accompanying drawing in which:

Fig. 1 is a view, partly diagrammatic, showing a control system constructed in accordance with my invention, and Fig. 2 is a top plan view of the burner thereof.

In the drawing, reference numeral I indicates a pipe leading from a suitable source of gas sup ply to the intake side of a control valve housing 2. The housing 2 is provided with an intake chamber 3 and a discharge chamber 4 which chambers are separated by a partition 5. An opening in the partition 5 is controlled by a valve 1 having stem 8 which extends through the chamber 4 and projects, through an opening 9 provided in a guide boss l6, into a chamber H where it contacts a diaphragm [2. The chamber H is formed of a flange l3 projecting down-' wardly and outwardly from the housing 2 and a chamber i4 is provided below the diaphragm by a cup-shaped member l5 attached to the flange I3 by screws I6. The diaphragm I2 is clamped between flange l3 and cup I5 to form a flexible wall between chambers H and I4.

A tube I7 is connected to the supply pipe I ahead of the control valve 1 and leads to the interior of a housing I8 in which is positioned a thermostatically controlled pilot valve IS. A pilot burner 20 is mounted on the housing i8 and is connected with a chamber 2! above the valve [9 by way of a restricted orifice 22. Also con nected with the space 2| is a tube 23 which leads to a control device 24 the details of which are not shown but which may be any suitable waterfiow, thermostatic, electric, steam-pressure or vacuum-controlled valve, depending upon the particular appliance in which the system is to be utilized. For example in a domestic storage type hot water heater, the control device 24 will be a thermostatically actuated valve responsive to the temperature of the water and so arranged that when the water is cold and heat is desired the valve will be in open position maintaining communication between tube 23 and a passage 25 which passage leads by Way of an adjustable orifice 26 to the lower diaphragm chamber Id. The diaphragm chamber l4 constitutes a pressure chamber and is provided with a bleed orifice 21 which permits communication between the pressure chamber l4 and the upper chamber II. A tube 28 connects the upper chamber H with a bleed burner 29 which forms a portion of one of' burner 20, the valve 19 will be in open position permitting a flow of gas through the restricted orifice 22 to the pilot burner, and also permitting a flow of gas from the chamber 2| by way of passage 23 to the control device 24. If this device is in open position, that is has been opened in response to a demand upon the burner asfor example by the cooling of the water in a storage system or by the flow of water through an instantaneous system, it will permit the passage of gas from the tube 23 to the tube 25 and thence to the lower diaphragm chamber l4. A pressure will be built up within this chamber faster than the orifice 21 can bleed the gas to the upper chamber II. The diaphragm I2 will rise, moving the stem 8 upwardly and thereby opening the valve 1. Gas will now flow from the intake side of the valve to the discharge side and thence by way of pipe 32 to the various jet orifices of the burner.

When the demand upon the burner has ceased, the control valve 24 will close communication between the tube 23 and tube 25 and the pressure within the chamber I4 will be dissipated through the bleed hole 21 and tube 28 so that the valve '1, and attached parts, will fall of their own weight closing the valve and cutting ofi the flow of fuel to the main burner. It will also be seen that in the event the flame at the pilot burner 20 becomes extinguished, the valve [9 will close communication between the tube [1 and the tube 23 with the result that pressure within the diaphragm chamber I4 will no longer be maintained. Furthermore, in the event of breakage, material leakage, or clogging of any of the connecting elements between the supply line I and the'lower diaphragm chamber l4, the valve 1 will also close. For this reason the system above described is superior to any arrangement in which the closure of the main gas valve is dependent upon pressure within any portion of the diaphragm chamber.

A material advantage of the structure shown resides .in the fact that some leakage through opening 9 around the stem 8 will not affect the operation of the device since such leakage will only occur when the valve 1 is in open position and this will be vented off by the tube 28 to the bleed burner 28 so that pressure which would otherwise oppose the flexing of the diaphragm will not be built up in the upper diaphragm chamber H. Thus no packing will be required around the valve stem 8. On the contrary, it is permissible to have a relatively loose flt at this point, permitting free movement of the stem 8 through opening 9, so that the annular boss l constitutes a guide in which valve stem 8 moves freely without danger of binding or sticking.

A further advantage of the present invention resides in the fact that if the opening through the adjusting means 26 is so limited that it is but slightly larger than the bleed hole 21, the opening of the valve I will be efiected very gradually, permitting at first a small flow of gas to the main burner 3| until the flame from the pilot jet has spread to all of the orifices forming the main burner jets before the full flow of gas to this burner is effected. This function which is particularly useful in connection with luminous flai'rle burners has heretofore been achieved in other ways, as for example by providing the valve 1 with a depending skirt as shown in the above mentioned Patent 2,135,585. The present invention effects this same result without the use of additional structural elements and in a manner which permits the adjustment of the rate of. opening of the gas valve as desired, for by suitably proportioning the sizes of the two openings 26 and 21, the valve 1 will open rapidly or slowly upon the opening of the control valve 24. For example, if the orifice 26 is a #58 opening and the orifice 21 is a #60 opening, then the rate at which gas escapes from the chamber I4 below the diaphragm [2 will be almost as rapid as the rate of supply and the valve will rise slowly. Thus a low flame is given time to spread over the entire face of the burner before the full flow of gas thereto.

Although the invention has been described and illustrated with respect to a single embodiment of the invention, other embodiments and modifications within the scope of the appended claims will be obvious to those skilled in the art from a consideration of the teachings herein set forth.

Having thus described the invention, what is claimed is:

1. A control system for a gas burner including a gas supply line leading to said burner, a casing forming a valve housing connected in said line, a valve in said casing controlling the flow through said line, a stem for said valve projecting loosely through a wall of said casing, means forming a chamber enclosing the projecting end of said stem, said chamber having a flexible wall contactin said end of said stem, means to apply fluid pressure to the side of said wall remote from said valve to flex said wall to move said valve in an opening direction, and means to discharge gases from said chamber to a point adjacent said burner whereby gas leaking through the opening around said valve stem is prevented from opposing the flexing of said wall.

2. A control system for a gas burner including a gas supply line leading to said burner, a casing forming a valve housing connected in said line, a valve in said casing controlling the flow through said line, a stem for said valve projecting loosely through a lower wall of said casing, means forming a chamber enclosing the projecting end of said stem, said chamber having a flexible wall contacting said end of said stem, means forming a pressure chamber on the opposite side of said Wall for flexing the same to move said valve in an opening direction, passaged means connected to said gas supply line on the intake side of said valve for supplying gas to said pressure chamber, means to control the flow of gas through said passaged means, means forming a restricted passage for bleeding gas from said pressure chamber, and means for discharging both the bleed gas and the gas leaking around said valve stem into the combustion space of said burner, whereby said valve is opened by pressure in said pressure chamber and is closed by gravity upon failure of such pressure.

HERBERT J. LONG. 

